1. Field of the Invention
The present invention relates to a pen-shaped input apparatus for inputting figures, symbols, characters and the like into a data processing device, such as a computer.
2. Description of the Related Art
Conventionally, a keyboard, mouse, digitizer, light pen, and tablet, etc. have been used as an input apparatus employed in a computer apparatus or the like. Such computer apparatus needs to be small-sized, and there is a growing need for a portable terminal instrument as the number of users increases year by year. Consequently, a small-size input apparatus is also required.
There is a limitation on making the keyboard small-sized from the viewpoint of the human interface, and a keyboard is not a practical input apparatus for a portable terminal instrument. Furthermore, although the mouse can be made in a small-size and used as a pointing device, it is not suitable for inputting figures and characters, etc. into a data processor.
For this reason, on many occasions, a pen-shaped input apparatus employing a tablet and pen have been adopted as the input apparatus for a portable terminal instrument. However, it is difficult to reduce the size of the tablet.
To overcome the problem of tablet size, tabletless input apparatuses have been developed such as, for instance, a pen-shaped computer input apparatus as disclosed in Japanese Laid-open Patent Publication No. 6-67799/1994, a data input apparatus as disclosed in Japanese Laid-open Patent Publication No. 7-84716/1995, a handwriting input apparatus as disclosed in Japanese Laid-open Patent Publication No. 7-200127/1995, and a pencil-shaped input apparatus as disclosed in Japanese Laid-open Patent Publication No. 6-230886/1994.
The pen-shaped computer input apparatus disclosed in Japanese Laid-open Patent Publication No. 6-67799/1994 senses the movement direction and the movement amount of the input apparatus by use of an acceleration sensor and then compensates for an influence exerted on the movement direction and the movement amount sensed by the acceleration sensor by the action of the pen-shaped computer input apparatus' rotation by use of a piezoelectric vibration gyroscope.
Furthermore, the data input apparatus disclosed in Japanese Laid-open Patent Publication No. 7-84716/1995 senses the movement direction and the movement amount of the apparatus on the basis of signals showing the polarity and the amplitude respectively transmitted from vibration gyroscopes perpendicularly disposed to each other.
Furthermore, the handwriting input apparatus disclosed in Japanese Laid-open Patent Publication No. 7-200127/1995 obtains a movement direction and a movement distance (amount) on the basis of the signals respectively transmitted from two acceleration sensors.
Furthermore, the pencil-shaped input apparatus disclosed in Japanese Laid-open Patent Publication No. 6-230886/1994 disposes a couple of acceleration sensors on different positions of the pen shaft, and obtains a movement direction and a movement distance of the pen's tip end. In this apparatus, the influence due to the mounting position of the acceleration sensors is compensated on the basis of the output from the couple of acceleration sensors.
And further, a position sensor disclosed in the published specification of Japanese Laid-open Patent Publication No. 7-294240/1995, which does not directly relate to the pen-shaped input apparatus is used, for instance, in a game machine for sensing the moving speed, position and attitude of the head portion of human body, and the position sensor comprises acceleration sensors for respectively sensing the accelerations in the X-axis direction, the Y-axis direction, and the Z-axis direction and gyroscopes for respectively sensing the angular velocities around the X axis, the Y axis, and the Z axis. This apparatus performs a strap-down type operational calculation on the basis of the accelerations and the angular velocities detected by those sensors and detects the moving speed, position, attitude, and direction of the head portion of the human body.